“Clearly the victim was very shaken by what’s happened to her but this does appear to be an isolated incident.

“Now we have the CCTV image, we’re making an appeal for anyone who recognises the man or anyone who may have seen a man matching the description of our offender around Cosham that Sunday evening.”

Anyone with information is asked to contact Portsmouth CID at Fratton police station on 101 or 0845 045 45 45 from outside Hampshire and the Isle of Wight. You can also call the anonymous Crimestoppers charity on 0800 555 111.